[X86] Tune LEA usage for Silvermont

According to Intel Software Optimization Manual on Silvermont in some cases LEA
is better to be replaced with ADD instructions:
"The rule of thumb for ADDs and LEAs is that it is justified to use LEA
with a valid index and/or displacement for non-destructive destination purposes
(especially useful for stack offset cases), or to use a SCALE.
Otherwise, ADD(s) are preferable."

Differential Revision: http://reviews.llvm.org/D3826

llvm-svn: 209198

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/X86Subtarget.h b/llvm/lib/Target/X86/X86Subtarget.h
index 5d2dcefb079..8ec680efff8 100644
--- a/llvm/lib/Target/X86/X86Subtarget.h
+++ b/llvm/lib/Target/X86/X86Subtarget.h
@@ -178,6 +178,9 @@ protected:
   ///             address generation (AG) time.
   bool LEAUsesAG;
 
+  /// SlowLEA - True if the LEA instruction with certain arguments is slow
+  bool SlowLEA;
+
   /// Processor has AVX-512 PreFetch Instructions
   bool HasPFI;
   
@@ -315,11 +318,13 @@ public:
   bool padShortFunctions() const { return PadShortFunctions; }
   bool callRegIndirect() const { return CallRegIndirect; }
   bool LEAusesAG() const { return LEAUsesAG; }
+  bool slowLEA() const { return SlowLEA; }
   bool hasCDI() const { return HasCDI; }
   bool hasPFI() const { return HasPFI; }
   bool hasERI() const { return HasERI; }
 
   bool isAtom() const { return X86ProcFamily == IntelAtom; }
+  bool isSLM() const { return X86ProcFamily == IntelSLM; }
 
   const Triple &getTargetTriple() const { return TargetTriple; }